WASHINGTON – Under pressure to do more for hurricane-ravaged Puerto Rico, President Donald Trump on Thursday waived federal restrictions on foreign ships' transportation of cargo to the island. He tweeted that relief supplies are getting through.

Trump has a problem with Puerto Rico’s ‘massive debt’ – but $33 million of it came from his failed golf course there pic.twitter.com/Bwb3eW2At1

"The electric power grid in Puerto Rico is totally shot. Large numbers of generators are now on Island. Food and water on site," he wrote.Hurricane Maria hit the U.S. territory more than a week ago, leaving it without power and its roughly 3.4 million residents short on fuel and other supplies. Trump came under withering fire earlier this week for what some critics said was his slow response to an escalating humanitarian crisis.Republicans and Democrats had urged Trump to waive a little-known federal law called the Jones Act that prohibits foreign-flagged ships from shuttling goods between U.S. ports.Trump spokeswoman Sarah Huckabee Sanders said Trump was responding to a request from Puerto Rico Gov. Ricardo Rossello, and that the waiver would go into effect immediately.Rossello responded on Twitter to Trump's action: "Thank you @POTUS."

Advocates who pressed for the waiver have said it could get desperately needed supplies delivered to the island more quickly and at less cost.Acting Homeland Security Secretary Elaine Duke had waived the law earlier this month to help ease fuel shortages in the Southeast following hurricanes Harvey and Irma. That order included Puerto Rico, but expired last week shortly after Maria struck.The Trump administration had said a waiver was not needed for Puerto Rico because there were enough U.S.-flagged ships available to ferry goods to the island.

Trump told reporters Wednesday that his administration was looking at a new waiver, but he said, "We have a lot of shippers and a lot of people and a lot of people that work in the shipping industry that don't want the Jones Act lifted."Sen. John McCain, Republican from Arizona, in a tweet, noted that the administration "has finally waived" the Jones Act. "Now Congress must repeal this law to aid long-term recovery."